Reciprocity Calibration of Microphones under High Ambient Pressures

Abstract

The purpose of this study was to demonstrate a technique for primary calibration of microphones under high ambient pressures and various gas mixtures. The reciprocity calibration technique was chosen for calibrating a piezoelectric microphone to 600 feet in a helium-gas mixture and depth changes were applied to the basic reciprocity formula. Using the reciprocity calibration technique with a piezoelectric microphone it was found that sensitivity decreased at frequencies below 2000 Hertz as pressure increased. At the pressures encountered from 300-600 feet, the sensitivity of the microphone was stable from 3000 to 8000 Hertz. Between the surface and 600 feet depths, there was approximately a 15 to 18 dB loss in sensitivity.

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Document Details

Document Type
Technical Report
Publication Date
Jul 21, 1971
Accession Number
AD0749318

Entities

People

  • Russell L. Sergeant
  • Thomas Murry

Organizations

  • Naval Submarine Medical Research Laboratory

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Abstracts
  • Acoustic Equipment
  • Acoustics
  • Biomedical Research
  • Calibration
  • Diagrams
  • High Pressure
  • Hyperbaric Chambers
  • Hyperbaric Conditions
  • Measurement
  • Microphones
  • Navy
  • Pressurization
  • Schematic Diagrams
  • Sea Water
  • Standards
  • Transducers

Readers

  • Acoustics.
  • Aerospace Test and Evaluation
  • Materials Science and Engineering.